When motion picture and still photographic films are subjected to physical and mechanical handling or treatments, involving friction, there is a build-up of static electricity on the surface of these films. This static electricity leads to dust being fixed on the surface of the film with to a risk of discharge, sparking or even ignition when the charge becomes high. These phenomena are particularly detrimental to the quality of the final image. For this reason, a great number and variety of substances have been proposed in the prior art as antistatic agents. These substances are mixed with various carriers, binders or additives in order to produce antistatic compositions which are then used to form antistatic layers on photographic supports, elements or materials. A review of antistatic agents useful in photography is given in Research Disclosure, No 501, September 1994, publication 36544, page 520 and in Research Disclosure No 316, dated 1990, p. 687.
There is also in Research Disclosure No 247, dated 1984, p. 550, a description of silicon-containing polymers which improve antistatic properties, adhesion between constituent layers, and coatability onto photographic elements.
The very abundance of the substances proposed as antistatic agents in these publications suggests that it is difficult to find antistatic substances which afford complete satisfaction. Some substances interreact with the components of the photographic material and the image formation mechanism, others have insufficient stability, or exude from the layers where they were incorporated, others are difficult to formulate because they require grinding and dispersal operations with organic solvents, and finally many have insufficient antistatic action.
Antistatic compositions for photographic materials, comprising dispersions of a particulate, water-dispersible; conductive polymer, and latex are described in Research Disclosure No 189, dated 1980, p. 29 to 31. A typical composition contains ethylene glycol dimethacrylate-N-vinylbenzyl-N,N,N-trimethylammonium chloride (7:93% mole) and 2-chloroethyl methacrylate-glycidyl methacrylate-lauryl methacrylate (49:20:31). These components, when they are subjected to certain conditions, provide an optically clear layer which is conductive and resistant to abrasion.
The applicant recently discovered a novel substance which is a fibrous inorganic polymer of aluminium and silicon, and has antistatic properties. This substance and a method for its synthesis are described in PCT patent application EP 9504165 (95935962.1) and entitled "New polymeric conductive alumino-silicate material, element comprising said material and process for preparing it".
The object of the present invention is a novel antistatic composition using the substance of the aforementioned patent application, having improved mechanical properties.